Here's venom in your eye: Spitting cobras hit their mark

Jan 22, 2009

Spitting cobras have an exceptional ability to spray venom into eyes of potential attackers. A new study published in Physiological and Biochemical Zoology reveals how these snakes maximize their chances of hitting the target.

The name "spitting cobra" is a bit of a misnomer. Cobras don't actually "spit" venom, says the study's lead author Bruce Young, director of the Anatomical Laboratory in the Department of Physical Therapy at the University of Massachusetts, Lowell. Muscle contractions squeeze the cobra's venom gland, forcing venom to stream out of the snake's fangs. The muscles can produce enough pressure to spray venom up to six feet.

There are no points for distance, however. To be effective, venom must make contact with an attacker's eyes, where it causes severe pain and possibly blindness. Previous studies have found that cobras hit their targets with alarming frequency—nearly 100 percent accuracy from 60 centimeters.

Dr. Young and his colleagues, Melissa Boetig and Dr. Guido Westhoff, have found the secret to the cobra's success.

Cobra venom does not hit a victim in one spot. Instead, the venom lands in complex geometric patterns. This is no accident, according to the study. The patterns are actively produced by the cobra.

Dr. Young and his team used high-speed photography and electromyography (EMG) to detect contractions of head and neck muscles. They found that cobras engage their head and neck muscles a split second before spitting. The muscle activity rotates the head, and jerks it from side to side and back again, producing complex venom patterns.

"The venom-delivery system functions to propel the venom forward while the [head and neck] muscles produce rapid oscillations of the head that … disperse the venom, presumably maximizing the chance that a portion of the spat venom will contact the eye," the authors write.

The ability to actively disperse venom means that cobras don't need dead aim on the eye. They just need to be in the ballpark.

The paper appears in an issue of Physiological and Biochemical Zoology on the focused topic "Functional Consequences of Extreme Adaptations." PBZ is edited by Dr. James Hicks of the University of California, Irvine and published by the University of Chicago Press.

Source: University of Chicago

Explore further: Researchers collect soil samples from around the globe in effort to conduct fungi survey

add to favorites email to friend print save as pdf

Related Stories

Audi to develop Tesla Model S all-electric rival

11 hours ago

The Tesla Model S has a rival. Audi is to develop all-electric family car. This is to be a family car that will offer an all-electric range of 280 miles (450 kilometers), according to Auto Express, which ...

New largest number factored on a quantum device is 56,153

13 hours ago

(Phys.org)—Researchers have set a new record for the quantum factorization of the largest number to date, 56,153, smashing the previous record of 143 that was set in 2012. They have shown that the exact same room-t ...

Recommended for you

Parasitic worm genomes: largest-ever dataset released

15 hours ago

The largest collection of helminth genomic data ever assembled has been published in the new, open-access WormBase-ParaSite. Developed jointly by EMBL-EBI and the Wellcome Trust Sanger Institute, this new ...

Male sex organ distinguishes 30 millipede species

16 hours ago

The unique shapes of male sex organs have helped describe thirty new millipede species from the Great Western Woodlands in the Goldfields, the largest area of relatively undisturbed Mediterranean climate ...

How can we avoid kelp beds turning into barren grounds?

19 hours ago

Urchins are marine invertebrates that mould the biological richness of marine grounds. However, an excessive proliferation of urchins may also have severe ecological consequences on marine grounds as they ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.